From the Carnegie Institution , where soda pop science is like a carbonic acid trip, they say (thanks to modeling) we have to make big changes: “To save coral reefs, we need to transform our energy system…” while equating natural dissolution of CO2 into seawater with carbonation of soda pop, done under pressure and reduced temperature, making it supersaturated. The process is described as:

The amount of a gas like carbon dioxide that can be dissolved in water is described by Henry’s Law. Water is chilled, optimally to just above freezing, in order to permit the maximum amount of carbon dioxide to dissolve in it. Higher gas pressure and lower temperature cause more gas to dissolve in the liquid. When the temperature is raised or the pressure is reduced (as happens when a container of carbonated water is opened), carbon dioxide comes out of solution, in the form of bubbles.

While weak carbonic acid does get formed with CO2 dissolution in water [CO2 + H2O H2CO3 ] the majority of the carbon dioxide is not converted into carbonic acid, remaining as CO2 molecules, which is why it outgasses so easily when a non-chemical catalyst is applied, like vibration. Carbonic acid does not make the soda pop “fizzy”; it is the fact that it is supersaturated, and stored in a way to seal pressure preventing gas escape and maintaining the supersaturation. It is pressure and temperature that drive the main outgassing process, as anyone who as left an open can of soda pop in their car during a hot summer can attest.

Major changes needed for coral reef survival

Washington, D.C.—To prevent coral reefs around the world from dying off, deep cuts in carbon dioxide emissions are required, says a new study from Carnegie’s Katharine Ricke and Ken Caldeira. They find that all existing coral reefs will be engulfed in inhospitable ocean chemistry conditions by the end of the century if civilization continues along its current emissions trajectory. Their work will be published July 3 by Environmental Research Letters.

Coral reefs are havens for marine biodiversity and underpin the economies of many coastal communities. But they are very sensitive to changes in ocean chemistry resulting from greenhouse gas emissions, as well as to coastal pollution, warming waters, overdevelopment, and overfishing.

Ricke and Caldeira, along with colleagues from Institut Pierre Simon Laplace and Stanford University, focused on the acidification of open ocean water surrounding coral reefs and how it affects a reef’s ability to survive.

Coral reefs use a mineral called aragonite to make their skeletons. It is a naturally occurring form of calcium carbonate, CaCO3. When carbon dioxide, CO2, from the atmosphere is absorbed by the ocean, it forms carbonic acid (the same thing that makes soda fizz), making the ocean more acidic and decreasing the ocean’s pH. This increase in acidity makes it more difficult for many marine organisms to grow their shells and skeletons, and threatens coral reefs the world over.

Using results from simulations conducted using an ensemble of sophisticated models, Ricke, Caldeira, and their co-authors calculated ocean chemical conditions that would occur under different future scenarios and determined whether these chemical conditions could sustain coral reef growth.

Ricke said: “Our results show that if we continue on our current emissions path, by the end of the century there will be no water left in the ocean with the chemical properties that have supported coral reef growth in the past. We can’t say with 100% certainty that all shallow-water coral reefs will die, but it is a pretty good bet.”

Deep cuts in emissions are necessary in order to save even a fraction of existing reefs, according to the team’s results. Chemical conditions that can support coral reef growth can be sustained only with very aggressive cuts in carbon dioxide emissions.

“To save coral reefs, we need to transform our energy system into one that does not use the atmosphere and oceans as waste dumps for carbon dioxide pollution. The decisions we make in the next years and decades are likely to determine whether or not coral reefs survive the rest of this century,” Caldeira said.

###

The World Climate Research Programme’s Coupled Model Intercomparison Project is provided support from the U.S. Department of Energy, which developed a software infrastructure in partnership with the Global Organization for Earth System Science Portals.

“The computer results were predetermined.” “They set out to prove the hypothesis contrary to the scientific method.” “They did not entertain the null hypothesis.” “Despite this they convinced the world that CO2 is a serious problem.”

Hmmm… and what exactly is that CaCO3 made of? Isn’t CO2 playing major role in its formation, too…?
World’s deposits of marble and calcite are not source of sea organisms’ shells. They are deposits of these from times when there were way more CO2 in the atmosphere than today.

I would like to post this, somewhat O/T but in the same theme. There has been major flooding in southern Alberta Canada now this cartoon popped up inferring so called “climate change” is to blame. Ignorance is amazing.

In the equatorial south pacific. the surface water is already saturated with CO2, no amount that is added to the atmosphere is going into this area of the ocean. It is nearly always coming out of the ocean surface as the sea water is warmed as it goes from East to West. This area of the ocean is adding CO2 to the atmosphere at a rate that is an order of magnitude greater than all the global anthropogenic emissions. The cold polar waters are sucking it up at a slightly less rate resulting in a slow global accumulation. These rates are always changing, some on an annual time scale, others, in decades, or centurys. The rate of temperature change is the controlling factor at a specific area, not just equilibrium at some “global temperature”.

None of this sinks in with the voting public who go out in their millions and vote for energy Armageddon.

A Facebook friend (kind liberal leftie, into every Greenie cause) posted a photo last week of some US demo, with young people carrying placards reading “STOP Climate Change”. It seems the ‘scientists’ are on around the same intellectual level

While weak carbonic acid does get formed with CO2 dissolution in water [CO2 + H2O H2CO3 ] the majority of the carbon dioxide is not converted into carbonic acid, remaining as CO2 molecules, which is why it outgasses so easily when a non-chemical catalyst is applied, like vibration.

This is not completely true the overall dissolution process is as follows:

CO2 + H2O ⇋ H2CO3
H2CO3 ⇋ H+ + HCO3-
HCO3- ⇋ H+ + CO3–

Under present atmospheric and oceanic conditions the majority is in the form of bicarbonite ion (HCO3-).

My radical leftist facebook friend has been on about ocean acidification for more than a year now. Setting aside the silly comment in the article, is there any hard science on acidification, one way or another?

Dissolution of CO2 in water is CO2 + H2O H2CO3
H2CO3 is carbonic acid which fairly rapidly dissociates into H3O+ and HCO2- (pKa1 ~3.6)
The reaction is driven to the right by “atmospheric pressure” and temperature. When you take the sody pop back to atmospheric, the formation of CO2 is rapid as seen by the bubbles.
So, he is sort of right about that and it is a “grade school” explanation. The chemistry of CO2 in water is a bit more complex, but it starts with the simple explanation offered.

Hmmm… and what exactly is that CaCO3 made of? Isn’t CO2 playing major role in its formation, too…?
World’s deposits of marble and calcite are not source of sea organisms’ shells. They are deposits of these from times when there were way more CO2 in the atmosphere than today.

In fact, the primary deposits of CaCO3 (comes as limestone, marble) are biological in origin. Old reefs and calcareous muck, The aragonite in coral and similar critters is in fact unstable at STP and gradually switches to calcite over long time spans once the material is no longer part of a living organism. Water saturated with CaCO3 precipitates calcite in cool conditions and aragonite in warmer conditions. Biological processes in coral and bivalves tend to force the production of aragonite rather than calcite regardless of the mineral’s preferred habit.

It appears that by and large, these modelers are not terribly concerned about biological reality. The very same facts that indicate that the planet would already be dead if the CAGW hypothesis made sense, also show that modern corals and shell fish are descended from populations that “survived” oceans that were exposed to several times the concentration of CO2 that we see at present. In fact many of these limestone and marble formations developed during eras of high atmospheric CO2.

The pH of carbonated water is 3-4, so adding CO2 (under pressure, etc) acidifies the water. The old story was that the EPA was going to define the hazardous characteristic of corrosive as liquids with pH of ~3.5 until someone pointed out that carbonated beverages would be classified as hazardous wastes. So, adding CO2 to sea water will decrease the pH. I believe we are seeing decreases from 8.3 to 8.2 (???). Since 8.2<8.3 the water is less basic by their lights it must be more acidic. A real piece of scary propaganda, lying definition.

In the Cretaceous Era, which ended 65 million years ago, the CO2 levels varied between 1,200 and 2,000ppm, or 3-5 times today’s levels. The chalk cliffs of SE England are part of a Cretaceous limestone bed, several thousand feet thick. The rest of the world is riddled with Cretaceous limestone reefs.

The geological record is the alarmists’ nemesis, as it regularly exposes their scare stories as BS.

In geological time carbon dioxide levels in the atmosphere have been very much higher than now. Indeed, the levels today are close to an all-time low.
I live within a 30 minute or so drive from Much Wenlock which is the home of the Much Wenlock Limestone Formation. At the time (the Silurian, c.425 Ma) the carbon dioxide level was in the thousands of ppm and corals thrived. Patch corals are abundant in the shallow water limestone, indeed, the extra pure calcium carbonate from coral reefs was mined and quarried to help iron production for the Industrial Revolution. The only time when corals did not exist were at the end of the Permian (c. 250 Ma) following the mass extinction of many forms of life. The Paleozoic corals died out and within a few tens of million years the modern, Scleractinia, corals evolved to fill the niche left behind.

Thus, through hundreds of millions of years corals have lived and thrived with atmospheric levels of carbon dioxide an order of magnitude higher (or more) than at present.

Part of the reason, no doubt is that adding carbon dioxide to sea water does not make it acidic. Seawater is alkaline and is an acid/alkali buffer. Thus, addition or removal of carbon dioxide has only a minor effect on pH.

I don’t know what the alkalinity of seawater is but before it’s pH would actually decrease it would need to be overcome.
PS “Alkalinity” here describes the ability of seawater to resist a change in pH. Carbonic acid could react with a variety of chemicals in the ocean that would “use it up” before additional carbonic acid would make hydrogen ions available to actually lower pH. (I’m someone here could explain better.)

I’ve interacted with Ken in the past. He believes that all the gigantic Earthly sources and sinks are 1:1 identically and optimally matched such that anthropogenic CO2 is partially choked down by the oceans (acidifying the poor oceans) while the remainder accumulates in the atmosphere.

About 1% of CO2 entering the water becomes carbonic acid, at least temporarily. If the CO2 rises 100 ppm in the next 100 years, that means 1 part per million in the seawater (the surface water, at least) will be extra carbonic acid. In order to change the water at depth this will have to continue for about 800 years. I don’t think this warrants as much attention as is claimed.

not sure if anyone at this post truly cares, but some of the comments above belie some serious misunderstandings about carbonate chemistry, how the world works, and basic geological observations. Over short time intervals, a sudden increase in CO2 to the atmosphere (or for that matter to the ocean) will definitely increase the total carbon content of the atmosphere and ocean, and decrease ocean pH. In fact, this can be observed in records taken over the last 50 years, or a “sody pop” (which typically has a pH of <4). On longer time-scales, however, one has to consider the cations (notably Ca2+), which are supplied from rivers. So what happens when you have a world where carbon inputs increase slowly is indeed greater carbonate precipitation (and the chalks and limestones of the UK) because the greater inputs of carbon and calcium have to be balanced. But just do a google search on the Paleocene-Eocene thermal maximum (PETM) ca. 55 million years ago and you can see what happens when carbon is rapidly added to the atmosphere and ocean — there is indeed widespread carbonate dissolution because of a drop in pH, followed by excess carbonate precipitation, as the cation effect kicks in. In other words, you have a basic theory for how things work and you have examples in the geological record that are entirely consistent with such theory. Please don't obfuscate things. If you really are perplexed by the concept of ocean acidification and carbonate dissolution and precipitation — here's a 6th grade science experiment. Go to the beach and get a shell. Put it in a bottle of sparkling water. Watch it slowly dissolve. Add some Ca2+ and watch white particles precipitate.

I was in the Caribbean last year and guess what I saw from the airplane window, whitings! A natural phenomenon where CaCO3 precipitates directly out of the sea water and can only occur when the water is supersaturated with CaCO3. I would love to ask the authors when they expect the ocean to no longer be supersaturated with CaCO3, I’m sure the answer would be a blank stare. Are these the same authors that claimed that 75% (can’t remember the exact number) of the krill and plankton around Antarctica has disappeared since the 70s?

Roy, here are some grade school facts for you. The Earth was MUCH warmer during the PETM. The Earth was in a hot-house state where not even Antarctica was glaciated and the oceans still favored the precipitation of low-mag calcite, not aragonite. The Earth was warmer during the peaks of the previous interglacial period, evidenced by O18 isotopes, sea levels, and multiple lines of evidence showing that the Arctic was seasonally free of sea ice. The pH of the ocean has dropped 0.1 units since the beginning of the industrial revolution, which is actually not statistically significant. The diurnal variation of pH in the ocean is much greater and the seasonal variation is as well. So, please do yourself a favor and do not hold your breathe until the Earth returns to a hot-house/low mag calcite state.

I was in the Caribbean last year and guess what I saw from the airplane window, whitings! A natural phenomenon where CaCO3 precipitates directly out of the sea water and can only occur when the water is supersaturated with CaCO3.

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I’m not sure how this fits into the context of this post but calcium carbonate has a much lower solubility than calcium bicarbonate. In lime-soda water softening calcium oxide is added to the water to change calcium bicarbonate to calcium carbonate which then will precipitate. The process raises the pH. CO2 is then added to convert calcium carbonate back into calcium bicarbonate so that it doesn’t settle out in the distribution system.
Again, I’m not sure how this applies to the oceans but the process has been used for 100 years to treat drinking water.

There are well preserved Middle Devonian coral reefs there, when atmospheric CO₂ content was 2200 ppmv (8 times preindustrial level). That much about ocean acidification and its dire effect on reefs. Should we introduce tera rubbish as the new unit of nonsense?

I think Roy needs to understand some basic geological facts too. For a start the limestone deposits in the UK (e.g. Chalk and Carb.Limestone) are actually dead carbonate skeletal matter – NOT depositional carbonates (i.e. not from dissolution).

Did I miss it, or in the Carnegie Institute’s announcement that no pH values, nor their shift, were specified for the ocean? Typical – deal in generalities which scare people, but don’t provide substantive information on which they can make a judgment!

Rain is always acid. It is formed by absorption of CO2 in the atmosphere and is approximately a 10 percent carbonic acid solution. I don’t know of any calculations on how much CO2 is removed from the atmosphere by changes in the amount of water in the atmosphere or precipitation. How does variation in precipitation acidity affect the alkalinity of at least the surface layer of the ocean?

Although insoluble in ordinary water the calcium carbonate mineral – CaCO3 – dissolves in acidic carbonic solutions. Increasing the acidity of the oceans leads to fewer carbonate ions. By reducing the quantity of these raw materials, it slows the speed at which these creatures produce their calcite shells, making them less healthy, prone to dissolution and predators.

When these organisms die their calcareous shells fall to the bottom of the ocean, there they mix with silts to form sediments. Increased acidity dissolves their shells, the greater the acidity the less calcite reaches the sediment. The point at which the dissolution rate exceeds the supply rate of calcite produces the calcite-free red clays that clearly mark the PTEM, found by geologists across the world and recovered from dozens of deep sea drilling cores.

Examination of the remains of these shells (and those from other creatures) from the sediment layers below, in and above the acidic layer of 55 mya shows that the acidic layer marked a period of mass extinction for (or lack of recovery by) Phytoplankton, with dire consequences throughout the food chain.

Also, if I recall correctly, I am pretty sure that pH has to drop to at least 6 or below for CaCO3 solubility to occur significantly – and I am pretty sure it would take a lot to get ocean pH down to that level from current values of 8.2/8.3 !

Miniature reef aquariums have been kept in homes by hobbyists for a couple decades now. The original stumbling blocks were the lack of an efficient aerobic biological filtration system to convert toxic ammonia from animal wastes into still toxic nitrites, and then into less toxic nitrates; along with the unavailability of the powerful lighting systems necessary for the symbiotic algae within the coral polyps. There were some other details too: The corals were far more sensitive to nitrates then other marine animals so provisions were developed for that (constant water changes and/or nitrate consuming anaerobic filters), and reverse flow protein skimmers became common.

In a home the CO2 levels in the air are surprisingly higher than outside; I believe on the order of 25-50%. We could inform Obama that that comes from respiration. Anyway, since a marine aquarium must have a massive surface area differential in relationship to its volume compared to that of the ocean I would think that those home minireef aquariums would reflect this indoor CO2 concentration. Interestingly, the literature on these aquariums never bothers to bring this up as a problem. Could that perhaps be because it isn’t?

(dunno if the link will work- am trying new browser here!)
I’ll have to read it through, but there is an interesting graph (Figure 2) – which shows the Co2/pH relationship in water – strange that the ‘equilibrium point’ seems to be around pH 8.3 ??

Wherein it was claimed that humans are putting fossil fuel CO2 into the atmosphere at a rate massively greater than that which occurred in the petm, when allegedly all of the “carbon” stores in the Earth were injected into the atmosphere and oceans, resulting in temperature and ocean pH doom and gloom everywhere – although, fortunately, some adaptation allowed life to continue.

But if so, then where is the evidence that current CO2 additions and concentrations, even in toto, have had any effect on GMT or on the pH of oceans? And where is the evidence that carbon [C’s through and through or even CH3CH2CH2…CH3] is really CO2?

My radical leftist facebook friend has been on about ocean acidification for more than a year now. Setting aside the silly comment in the article, is there any hard science on acidification, one way or another?
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Yes Dr. Segalstad has a pdf at http://www.co2web.info/The distribution of CO2 between atmosphere, hydrosphere, and lithosphere; minimal influence from anthropogenic CO2 on the global “Greenhouse Effect”. Published 1996 In Emsley, J. (Ed.): The Global Warming Debate. The Report of the European Science and Environment Forum. Bourne Press Ltd., Bournemouth, Dorset, U.K. (ISBN 0952773406), pp. 41-50.
part 4. Chemical Laws for Distribution of CO2 in Nature
is the part you want to clik on. (Lots of good stuff on that site and it is not hard to read)

RT: I really do not understand your points. Yes, of course the PETM was MUCH warmer than today. But that’s precisely half the reason why it’s so interesting — it corresponds to a remarkable rapid warming, about 6 deg C above “background conditions” accordingly to multiple independent proxies. The other half of the interest is that it precisely corresponds to a massive input of carbon, with among multiple reasons being that one can see the impact of ocean acidification through carbonate dissolution.

Of course, such commentary should lead one to thinking why the background conditions were also much warmer than today …

And what does commentary on glacial-interglacial cycles d18O have to do with this? Well pretty much nothing — at the beginner level — but kudos for bantering around concepts that seem relevant. Obviously, there are changes in carbon cycling during and corresponding to glacial-interglacial cycles in d18O, as one can easily see in thousands of deep sea cores, but these changes, while really intriguing, do not represent external carbon inputs and outputs to the ocean and atmosphere.

Kev-in-UK: I really don’t understand your comment either. Where do you think significant carbonate accumulates other than through biological components? So, yes, the suggested grade school experiment is not a truly good analog, because it would not have biological precipitation of carbonate. But his completely misses the point.

DGP: Agree and good to know someone likes to actually experiment and think independently. After a grade school student came in curious about ocean acidification, I suggested to him to try it. He thought totally cool and interesting … and well … I guess you can read all the reasons above why it won’t work, except basic chemistry does not lie.

……So, adding CO2 to sea water will decrease the pH……
>>>>>>>>>>>>>>>>>>>>
You are leaving out one important fact. The oceans are not pure distilled H2O (Which upon sitting around exposed to the atmosphere has a pH that can go down as low as 5.0.)

The oceans are at a pH of 8.2 to 8.3 because they are BUFFERED!
Again see Dr Segalstad’s information at http://www.co2web.info/
specifically link (glad I check, it is now gives an error message DARN!)

Luckily this shorter version is still on the net.

The distribution of CO2 between atmosphere, hydrosphere, and lithosphere;
minimal influence from anthropogenic CO2 on the global “Greenhouse Effect”.
Tom V. Segalstad
Mineralogical-Geological Museum
University of Oslo

…..In addition there are a number of different aqueous metal complexes of lesser
concentrations.

A buffer can be defined as a reaction system which modifies or controls the value of an intensive (i.e. mass independent) thermodynamic variable (pressure, temperature, concentration, pH, etc.). Our carbonate system above will act as a pH buffer, by the presence of a weak acid (H2CO3) and a salt of the acid (CaCO3). The concentration of CO2 (g) and of Ca2+ (aq) will in the equilibrium Earth system also be buffered by the presence of CaCO3, at a given temperature. If the partial pressure of CO2 (g) is increased, the net reaction will go towards the right because of the Law of Mass Action. If the temperature changes, the chemical equilibrium constant will change, and move the equilibrium to the left or right. The result is that the partial pressure of CO2 (g) will increase or decrease. The equilibrium will mainly be governed by Henry’s Law: the partial pressure of CO2 (g) in the air will be proportional to the concentration of CO2 (aq) dissolved in water. The proportional constant is the Henry’s Law Constant, which is strongly temperature dependent, and lesser dependent on total pressure and salinity (Drummond, 1981).

Questions have been raised about how strong this buffer is. It has been postulated (Bolin & Keeling, 1963) that an increase in atmospheric CO2 will be balanced when only approximately one tenth of this is dissolved in the ocean. This postulate fails for a number of reasons. An increase in atmospheric CO2 will namely increase the buffer capacity of ocean water, and thereby strengthen the ocean’s capacity to moderate an increase of atmospheric CO2; maximum buffer capacity for the system CO2 – H2O is reached at 2.5 to 6 times the present atmospheric partial pressure of CO2, depending on temperature and alkalinity (Butler, 1982). According to Maier-Reimer & Hasselmann (1987) the borate system also increases the ocean storage capacity for CO2 by more than 20% over an ocean with the carbonate-system alone.

Furthermore, this carbonate buffer is not the only buffer active in the atmosphere / hydrosphere / lithosphere system. The Earth has a set of other buffering mineral reactions. The geochemical equilibrium system anorthite CaAl2Si2O8 – kaolinite Al2Si2O5(OH)4 has by the pH of ocean water a buffer capacity which is thousand times larger than a 0.001 M carbonate solution (Stumm & Morgan, 1970). In addition we have clay mineral buffers, and a calcium silicate + CO2 ø calcium carbonate + SiO2 buffer (MacIntyre, 1970; Krauskopf, 1979). These buffers all act as a “security net” under the most important buffer: CO2 (g) ø HCO3- (aq) ø CaCO3 (s). All together these buffers give in principle an infinite buffer capacity (Stumm & Morgan, 1970)…. http://www.co2web.info/ESEFVO1.pdf

That is why the Ocean Acidification scare is a crock. Unfortunately most lay people do not understand buffers.

Let’s see. The US Federal Government (Dept. of Energy) pays these “scientists” to produce a paper, the press release of which occurs the same week as the Head of the US Federal Government makes a speech, whose premise is supported by said paper.

>>>>>>>>>>>>>>>
Wundergound is run by Jeff Masters who is a card caring CAGW activist. (I have read his blog on occasion)

Wunderground’s Climate Change Position
Earth’s climate is warming. This time, humans are mostly responsible, and the overwhelming majority of climate scientists agree. Climate change is already causing significant impacts to people and ecosystems, and these impacts will grow much more severe in the coming years. We can choose to take economically sensible steps to lessen the damage of climate change, and the cost of inaction is much higher than the cost of action.

Here’s a cool photo from National Geographic showing how carbonate chemistry works across the PETM:

What you will hopefully see is light (carbonate) going very abruptly to dark (clay from dissolution of carbonate) to slowly getting lighter as the weathering feedback and calcium inputs kick in.

(Some will note from the photo that it is a “replica” core, and some will probably even further jump to the notion that this must therefore be some sort of conspiracy. You can, however, find photos of the actual core — and many others — that span the PETM in the public domain, or visit a core laboratory, or even go collect one).

Bruce: I actually somewhat agree with your comment, because the PETM seems to me an imperfect analog for what is happening today. My point was not to suggest the PETM as our future if several 1000’s of petagrams of carbon are added to the ocean and atmosphere, as will almost assuredly happen at current pace. Rather, my point was to note that there is a clear geological analog in which to test some basic theories, such as that purported by the article that initiated the thread. I strongly suspect that professor Caldeira knows basic carbonate chemistry, and much about the PETM, and for people to make non-sensical comments is not very illuminating.

Secondly, modelling is the term developed around 2005 to replace constructivism. It is less a matter of modelling as designed to accurately reflect reality than modelling designed to influence student’s perceptions of reality. In ways that will provoke them to take action to solve real world problems.

I have written about the NSF funded Understandings of Consequence. They are frequently not true but they are designed to meaningfully influence likely future behavior. Think of it as scince experiments to create beliefs and new values about how society can be restructured in the future. And why it should be.

And if that seems absurdly manipulative, it is. But it is still the intentions if you read beyond the Executive Summary in so much of what the NSF or Carnegie or Gates or Ford are funding in education.

From Segalstad:This postulate fails for a number of reasons. An increase in atmospheric CO2 will namely increase the buffer capacity of ocean water, and thereby strengthen the ocean’s capacity to moderate an increase of atmospheric CO2

I have never heard that a buffer capacity is increased by using its capacity…

That te buffer capacity of the oceans (surface) is “only” absorbing 10% of the change in the atmosphere is a matter of chemical equilibria, which makes that the alkalinity of the oceans can absorb ten times more CO2 for the same increase in the atmosphere than fresh water would do. That is the Revelle factor:

Higher gas pressure and lower temperature cause more gas to dissolve in the liquid. When the temperature is raised or the pressure is reduced (as happens when a container of carbonated water is opened), carbon dioxide comes out of solution, in the form of bubbles.

The Carnegie Institution is dangerously close to placing the horse back before the cart.

They have just described in a nutshell: rising temperature preceding CO2 increase.

Next thing you know, we’re gonna hear about a lag or something. Perhaps 800 years or some such. ;-)

Made an error, the solubility of CO2 in fresh water is 0.33% at 1 atm CO2, but CO2 in the atmosphere is only 400 microatm. Thus the real solubility in rainwater is only 0.000132%. Even less if stronger acids from sulphur and nitrogen are present…

Also, if I recall correctly, I am pretty sure that pH has to drop to at least 6 or below for CaCO3 solubility to occur significantly – and I am pretty sure it would take a lot to get ocean pH down to that level from current values of 8.2/8.3 !

(dunno if the link will work- am trying new browser here!)
I’ll have to read it through, but there is an interesting graph (Figure 2) – which shows the Co2/pH relationship in water – strange that the ‘equilibrium point’ seems to be around pH 8.3 ??

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Below a pH of 8.3 carbonates can be a mix of calcium bicarbonate and calcium carbonate. Above 8.3 the carbonates will be calcium carbonate and calcium hydroxide.
(Keep in mind that the pH does not drive the chemical reaction but is an indication of the reaction that has occurred. Again, I’m not sure how this applies to the post.)

Link on the relationship between CO2, carbonic acid, and bicarbonate, and carbonate.

The composition depends on the pH.
pH of 12 it is all in the Carbonate
pH of 8 it is all in the Bicarbonate
pH less than 4, it is all in the CO2.

To deionize water, we acidify the water by removing the Cations.
The CO2/Bicarb/Carbonate is now mostly in the CO2 form.
We can then strip the CO2 out with air.
The remaining anions are then removed with an anion bed.

Jokes and ridicule aside it’s clear that ocean ph varies wildly in different parts of the ocean on a daily basis. The natural swings are greater than that expected by 2100. Alarm over. Move along now folks, nothing to see here.

Here are some studies published this year on ocean acidification or should that be less alkalineification. :)

Abstract – Bethan M. Jones et. al – 12 April 2013
Responses of the Emiliania huxleyi Proteome to Ocean Acidification
….We employed an approach combining tandem mass-spectrometry with isobaric tagging (iTRAQ) and multiple database searching to identify proteins that were differentially expressed in cells of the marine coccolithophore species Emiliania huxleyi (strain NZEH) between two CO2 conditions: 395 (~current day) and ~1340 p.p.m.v. CO2……..Under high CO2 conditions, coccospheres were larger and cells possessed bigger coccoliths that did not show any signs of malformation compared to those from cells grown under present-day CO2 levels. No differences in calcification rate, particulate organic carbon production or cellular organic carbon: nitrogen ratios were observed….
doi:10.1371/journal.pone.0061868
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Abstract – T. Cyronak et. al. – April 2013
Groundwater and porewater as major sources of alkalinity to a fringing coral reef lagoon (Muri Lagoon, Cook Islands)

…This study quantifies the contribution of shallow porewater exchange (as quantified from advective chamber incubations) and fresh groundwater discharge (as traced by 222Rn) to total alkalinity (TA) dynamics on a fringing coral reef lagoon along the southern Pacific island of Rarotonga over a tidal and diel cycle….

…This study describes overlooked sources of TA to coral reef ecosystems that can potentially alter water column carbonate chemistry. We suggest that porewater and groundwater fluxes of TA should be taken into account in ocean acidification models in order to properly address changing carbonate chemistry within coral reef ecosystems.

…However, nearly all of this work has focused on the effects of future conditions on modern populations, neglecting the role of adaptation…..These results suggest that spatially varying selection may help to maintain genetic variation necessary for adaptation to future ocean acidification.
doi:10.1111/gcb.12251

Sea water is a complex buffer and carbonic acid is a weak acid. There has been no detectable change in ocean pH as a result of rising CO2. They also ignore the fact that all of this sea life evolved under MUCH HIGHER CO2 than there is now. I bet they would love it.

Photosynthesis is in fact an alkalizing process that raises the pH. In a bay or estuary, the pH on a sunny day can go to 10–11 from the normal pH of 8. Sea life is much more resilient, particularly in the presence of more FOOD (CO2). CO2 is plant food and gives the other organisms more to eat!

Of course pH doesn’t drive the processes. My point was based on the recollection (30+ years) that dissolution of carbonate requires pretty Low (as in acidic) pH values. In the back of my mind,I have some flag showing about magnesium carbonates too – though I have no idea why!!
Seriously,the whole oceanic acidification thing really bugs me, because AFAICR there has not been any geological evidence of an acidic ocean – and, as a geologist, rocks are everything in terms of past climate indication!

“Coral reefs use a mineral called aragonite to make their skeletons. It is a naturally occurring form of calcium carbonate, CaCO3. When carbon dioxide, CO2, from the atmosphere is absorbed by the ocean, it forms carbonic acid (the same thing that makes soda fizz), making the ocean more acidic and decreasing the ocean’s pH. This increase in acidity makes it more difficult for many marine organisms to grow their shells and skeletons, and threatens coral reefs the world over.”

[sigh].. Back to grade school – the lot of ‘em.

Bet they’ve never tried to dissolve an eggshell (calcium carbonate) in soda water. It won’t happen as the pH of 4 is too weak and the oceans will NEVER absorb that much CO2.

Ocean pH ranges between 7.9 and 8.3, depending on where you measure it. As mentioned here many times, warm water outgasses CO2 and cannot become acidic if Gorebull Warbling occurs.

Their “study” is another blatant falsehood and should be shot down in the courts.

“… there has not been any geological evidence of an acidic ocean – and, as a geologist, rocks are everything in terms of past climate indication!”

I am sorry, but this comment displays and perpetuates flat-out ignorance. In a few posts above, I provided a very clear geological example – the PETM – where the evidence for ocean acidification related to massive and rapid carbon input is overwhelming. If you choose to read the geological record incorrectly or close your eyes to the obvious, I cannot help you, but please then do not suggest that the rocks suggest otherwise: the rock record absolutely supports the concept of ocean acidification during massive and rapid input of carbon to the atmosphere and ocean.

To Higley7:

First sentence: yes, probably

Second sentence: why? Are you honestly going to state that you understand carbonate chemistry better than a Research Professor at Stanford University (where I think Caldeira is located).

Sixth sentence: A huge and likely erroneous jump in logic. This is because the statement conflates multiple concepts. One is assuming that rates of change in chemistry were similar in the past, which is almost assuredly wrong. Another is assuming that past cation concentrations are invariant over time. By such logic, if one pumps CO2 into a closed aquarium (a query from earlier post), corals would be perfectly happy. This is clearly not the case, and I welcome you to buy an aquarium, then put 100 quid on some coral or other carbonate secreting organisms, pump CO2 into the tank, and test for yourself. I think many scientists would be more than happy to reimburse your 100 quid should you be able to demonstrate that the pH stays the same and carbonate secreting organisms like this, because this would conflict with a massive amount of research on the topic.

Second paragraph just off tangent so no point in commenting.

To Olaf:

Indeed, actually try your suggested experiment. Now what you will have to recognize is that, in a closed system, such dissolution will only go so far. Nonetheless, if you weigh the mass before, put into soda water, dry and reweigh, you will realize that dissolution has occurred. Now bring this new found knowledge to an open system.

To all: My basic point is not that I advocate an opinion on what to do about ocean acidification (or to pull a silly notion from some posts “less basification”), but that the process absolutely is happening now and has occurred in the past. Basically, I just ask people to be educated, and then discuss concepts and ideas.

Apart from anything else you are deluded to believe that simple ocean acidification was the cause of the PETM -(chicken and egg and all that!) but also, it is considered that methane played a significant part in that episode.
as for the rest of your reply – I just did a quick search and found this (which confirms my recollection!)

from which I quote
”We don’t have good records of pH over this period, so it’s difficult to tell how much of the extinctions were caused by ocean acidification as opposed to the temperature change or decrease in dissolved oxygen that results from warming ocean water.”

I’m not going to argue – as I’m way out of time with modern geological research – but unless you post links to research confirming PETM was acidification based – I’ll rely on my memory!

…..From Segalstad:“This postulate fails for a number of reasons. An increase in atmospheric CO2 will namely increase the buffer capacity of ocean water, and thereby strengthen the ocean’s capacity to moderate an increase of atmospheric CO2″

I have never heard that a buffer capacity is increased by using its capacity…

That te buffer capacity of the oceans (surface) is “only” absorbing 10% of the change in the atmosphere is a matter of chemical equilibria, which makes that the alkalinity of the oceans can absorb ten times more CO2 for the same increase in the atmosphere than fresh water would do….
>>>>>>>>>>>>>>>>>>>>>>>
Segalstad is a geologist so you have to read what he said with that in mind.

….this carbonate buffer is not the only buffer active in the atmosphere / hydrosphere / lithosphere system. The Earth has a set of other buffering mineral reactions. The geochemical equilibrium system anorthite CaAl2Si2O8 – kaolinite Al2Si2O5(OH)4 has by the pH of ocean water a buffer capacity which is thousand times larger than a 0.001 M carbonate solution (Stumm & Morgan, 1970). In addition we have clay mineral buffers,….

I realize that mentioning the name of Segalstad is like waving a red flag but in this case he is correct. The ocean is full of particles of minerals washed into the sea by rivers eroding their way through the dirt and rock. When he says “An increase in atmospheric CO2 will namely increase the buffer capacity of ocean water, and thereby strengthen the ocean’s capacity” he is talking of CO2 helping to dissolve these particles and put them into solution as a buffer.
(The missing page is much better at explaining this.)

Of course pH doesn’t drive the processes. My point was based on the recollection (30+ years) that dissolution of carbonate requires pretty Low (as in acidic) pH values. In the back of my mind,I have some flag showing about magnesium carbonates too – though I have no idea why!!
Seriously,the whole oceanic acidification thing really bugs me, because AFAICR there has not been any geological evidence of an acidic ocean – and, as a geologist, rocks are everything in terms of past climate indication!

===========================================================
Sorry. Didn’t mean to “aim” at you. Just trying to add a bit of info that might apply or help. For years I was under the mistaken impression that pH drove the reactions.

In the back of my mind,I have some flag showing about magnesium carbonates too – though I have no idea why!!

===============================================================
Off the top of my head, the “red flag” may have to do with dolomite limestone which are calcium and magnesium carbonates rather than just calcium carbonate?

Roy says: @ June 28, 2013 at 5:29 pm
…..Basically, I just ask people to be educated, and then discuss concepts and ideas.
>>>>>>>>>>>>>>>>>>>>>
Back at you. The oceans are not sitting isolated in analytical grade glassware. They are part of a complex that includes not only the atmosphere but also ROCKS, Rocks that can and do erode and dissolve to form buffers.

A buffer is an aqueous solution consisting of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. Its pH changes very little when a small amount of strong acid or base is added to it and thus it is used to prevent changes in the pH of a solution. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications WIKI

As usual this is a lie by omitting part of the explanation. The interaction of the lithosphere with the atmosphere and oceans.

Mostly the lithosphere is too far away for the corals. Mixing between the deep ocean and the upper ocean is very slow so it take hundreds if not thousands of years for an equilibrium disturbed at the surface (increased CO2) to return to equilibrium.

Roy, I tried my eggshell in soda water experiment long ago. In 6 months nothing happened, even with daily manipulation to provide stirring. Eggshell remained intact and appeared no different on both sides. I don’t have a scale that can measure micrograms where a difference MIGHT be found, but any might be due to natural entropy, where regrowth of a living organism would overwhelm that.

In any case, water can only continue to be carbonated while above freezing, so pH levels can only drop to about 4, same as soda water unless volcanic activity has something to do with it, but that brings many other elements into the picture completely unrelated to atmospheric CO2 -> ocean.

Kev-in-Uk: No one said the PETM was caused by ocean acidification. Rather, the ocean acidification was caused by a rapid and massive input of carbon. This is well documented and discussed in abundant literature.

Gail: good grief, of course the lithosphere needs to be accounted for. Nobody has suggested otherwise. Indeed, that’s precisely why the carbonate records respond the way they do across the PETM. However, the interaction with the lithosphere is slow….

he is talking of CO2 helping to dissolve these particles and put them into solution as a buffer.

Yes, but one need to take into account the time frames involved: the ocean surface layer is in equilibrium with the atmosphere within 1-3 years, where the CO2 in solution only increases 10% for a CO2 doubling and decreases pH with only a few tenths of a pH unit. Not really helping much with the dissolution of clay particles etc.

The deep oceans (and vegetation) have much slower exchange rates and take excess CO2 away from the atmosphere with a decay rate of ~40 years half life time. The change in pH for the deep oceans is not even measurable for a CO2 doubling over decades.

The dissolution of carbonate rocks is a much slower sink for CO2. Even with a doubled concentration in the atmosphere and thus a doubled dissolution of carbonate rock, the decay rates are in the thousands of years. Other rock types dissolve much slower…

I thought this rubbish science had died with the Dodo. Ocean water chemistry is not this simple, these idiots have missed the most important part of the reaction, the bicarbonate formation, which increases pH to the normal band of 7.6-8.4, and is the building block used by corals to grow. It is at times of high atmospheric CO2 content that corals have thrived and formed the largest limestone formations.
As a matter of physics temperature is far more important to gas solubility than partial pressure. CO2 is but one gas available to dissolve with O2 and N2 far larger constituents and far more readily dissolve. All outgas if temperature rises.

As a matter of physics temperature is far more important to gas solubility than partial pressure.

A little careful here: it is temperature which influences the equilibrium pressure of CO2 in the oceans, but that is not more than 16 microatm/°C. Thus any increase of 1°C will lead to 16 ppmv increase in the atmosphere, which will restore the previous fluxes in and out of the oceans.

If the increase in the atmosphere – for whatever reason – increases with more than 16 ppmv while the increase in temperature is 1°C, then the releases of CO2 from the oceans (near the equator) will be reduced and the uptake (near the poles) will increase. Currently we are 100 ppmv above the temperature dictated equilibrium…

i learned in the 7th grade that a substance wasn’t acidic until its pH was under 7. and that the proper terminology for a base changing its pH was to say it was “less alkaline” or “more alkaline.” the only way the word “acidification” should come into play is if we’re talking about something with a pH under 7 (which the oceans arent), but of course it sounds really scary so thats why its used…

DR-I have located documents that make it clear that UNESCO is pushing all aspects of the media to coordinate with the UN system on the “messages” being pushed.

If it’s not a conspiracy since it is in the open, it is indisputably a matter of active, deliberate coordination. The UN name for it is media education and part of its goal is to squelch climate skepticism.

fhhaynie says: June 28, 2013 at 11:50 am
“In the equatorial south pacific. the surface water is already saturated with CO2, no amount that is added to the atmosphere is going into this area of the ocean. It is nearly always coming out of the ocean surface as the sea water is warmed as it goes from East to West. This area of the ocean is adding CO2 to the atmosphere at a rate that is an order of magnitude greater than all the global anthropogenic emissions. The cold polar waters are sucking it up at a slightly less rate resulting in a slow global accumulation. These rates are always changing, some on an annual time scale, others, in decades, or centurys. The rate of temperature change is the controlling factor at a specific area, not just equilibrium at some “global temperature””

I am very much interested in your comment. I have read where the tropical ocean bubbles at night; but I cannot find the article again. This is related to the non-biological production of calcium carbonate in the ocean. If you can provide me references to your statement “It is nearly always coming out of the ocean surface as the sea water is warmed as it goes from East to West”, I would certainly appreciate it.

John,
Use the difference in solubility of CO2 in sea water at say 20 C and 26 C ( 90W and 135W at 10S). That difference has to go somewhere and it is most likely to go into the atmosphere. Some will precipitate as CaCO3 and fall below the thermocline. Just take the amount in a cubic meter on the surface and divide by one month and you can get an estimate of the rate that is being emitted into the atmosphere from that area. These temperatures are always changing in different time scale cycles. I suggest you use the units of kg/m^2/year and compare those values to anthropogenic emission rates in the same units (assumes emissions are uniformly distributed over the surface of the earth).

Ferdinand Engelbeen says: June 29, 2013 at 4:24 am
“The dissolution of carbonate rocks is a much slower sink for CO2. Even with a doubled concentration in the atmosphere and thus a doubled dissolution of carbonate rock, the decay rates are in the thousands of years. Other rock types dissolve much slower…”
I am trying to understand about those thousands of years. When rain water dissolves carbon dioxide and forms a weak carbonic acid and enters the ground, it dissolves limestone and other forms of calcium carbonate (an exothermic reaction) and after a series of reactions enters the ocean as calcium hydroxide. I don’t believe that you are saying that this process takes a thousand years; so how do we get the thousands of years. If there were not some balancing in the system, we would already have seen a large shift in Ph.

From fhhainie:This area of the ocean is adding CO2 to the atmosphere at a rate that is an order of magnitude greater than all the global anthropogenic emissions.

That is right, as the equilibrium pressure of CO2 in the tropics may be as high as 750 microatm, that is 350 microatm higher than the partial pressure in the atmosphere of ~400 ppmv CO2 (the difference between partial pressure and ppmv is the % water vapour at sealevel).
Thus the increase in the atmosphere need to go as high as 750 ppmv before some net amount of CO2 will enter the ocean surface in these area’s.
See further Feely e.a. at:

and following pages, including maps for summer/winter and net exchanges between oceans and atmosphere.

Retired Engineer John says:
June 29, 2013 at 10:19 amI don’t believe that you are saying that this process takes a thousand years

The reaction of CO2 with carbonate rocks is that it forms bicarbonates which are soluble in water. The reaction is quite fast, that is not the limiting factor. The limiting factor is the small amounts of CO2 in rainwater: as calculated before, some 0.000132% at near freezing point.

Thus despite the large amounts of rain, the dissolution of carbonate rock is a quite slow process, so that even a doubling of the speed doesn’t remove large quantities of CO2 out of the atmosphere over short periods of time.

Think of the amount of time needed to dissolve the caves we see in carbonate rock formations, that is hundredthousands to millions of years.
The opposite also needs time: the buildup of the carbonate rock layers was mostly done in the Cretaceous by coccolithophores:

Ferdinand Engelbeen says: June 29, 2013 at 4:24 am
“The dissolution of carbonate rocks is a much slower sink for CO2. Even with a doubled concentration in the atmosphere and thus a doubled dissolution of carbonate rock, the decay rates are in the thousands of years. Other rock types dissolve much slower…”

I am trying to understand about those thousands of years. When rain water dissolves carbon dioxide and forms a weak carbonic acid and enters the ground, it dissolves limestone and other forms of calcium carbonate (an exothermic reaction) and after a series of reactions enters the ocean as calcium hydroxide.

I believe lab and field chemistry results show that heightened carbonic acid makes it easier for living organisms to form shells, but more swiftly dissolves their shells after death (returning the CaCO3 to the accessible mix), and slowing the build-up of limestone beds on the seafloor.

Just take the amount in a cubic meter on the surface and divide by one month and you can get an estimate of the rate that is being emitted into the atmosphere from that area.

That gives an idea about the probable amounts that can be emitted, not the rate of emissions. The rate is influenced by two main points: the difference in pCO2 between ocean surface (directly influenced by temperature) and the pCO2 (~ppmv) of the atmosphere at one side and the gas transfer velocity, mainly a matter of wind speed.
Diffusion speed of CO2 through water is very slow, so one need a large surface and thourough mixing of waters and between water and air to have a substantial exchange of CO2. See:

Ferdinand,
I’m well aware of the mechanisms of mass transfer in boundary layers. Only at low wind velocities should we expect those are significant controllers of rates. In any case, Measuring the loss of CO2 from a cubic meter of surface sea water as it takes a one month journey from 90W to 135W is a rate when divided by one month. The solubility relationship is taken as a function of atmospheric partial pressure and SST. This assumes little difference in partial pressure across the boundary layer. If the partial pressure differences across the boundary layer are greater (low windspeeds), the calculated rates would be lower. On the other hand, if the CO2 comes from deeper than one meter, the rates would be higher. Thanks, for the URL. They know they have a difficult time getting a good estimate of rates as a function of time and latitude.

What does Eli Rabbet mean when he says “Mostly the lithosphere is too far away for the corals.”? The lithosphere includes the crust and to my knowledge coral forms on the crust, albeit in shallower ocean waters.. Besides, the comment appears to bear no relationship to the remainder of the comment.

“Coral reefs use a mineral called aragonite to make their skeletons. It is a naturally occurring form of calcium carbonate, CaCO3. When carbon dioxide, CO2, from the atmosphere is absorbed by the ocean, it forms carbonic acid (the same thing that makes soda fizz), making the ocean more acidic and decreasing the ocean’s pH. This increase in acidity makes it more difficult for many marine organisms to grow their shells and skeletons, and threatens coral reefs the world over.”

Okay I get where the lime (CaO) comes from to make the skeletons of the coral reef and the shells for pelecypods, etc (chemical erosion on land and transportation by rivers to the sea plus some dissolution of existing calcium carbonate in the sea), but how can the creatures make it into aragonite? Oh, I see, they combine the lime with CO2 in the ocean water!!

CaO + CO2 => CaCO3 ta dahhhhh!!

So you need CO2 in the sea (which makes up 44% of the shells). Oh and the pH of the sea is highly buffered which means budging the pH away from its ~8 isn’t accomplished easily.

“A Brief Summary of Carbonate Buffer System Chemistry
Atmospheric CO2 dissolves in seawater and is hydrated to form carbonic acid, H2CO3. Carbonic acid is divalent; that is, it can undergo two de-protonation reactions to form bicarbonate (HCO3-), and carbonate (CO32-). The co-existence of these species in seawater creates a chemical buffer system, regulating the pH and the pCO2 of the oceans. Most of the inorganic carbon in the ocean exists as bicarbonate (~88%)”

Measuring the loss of CO2 from a cubic meter of surface sea water as it takes a one month journey from 90W to 135W is a rate when divided by one month.

pCO2 difference with the atmosphere taken below the surface (mostly from the cooling inlet of seaships) is the deciding factor, besides wind speed. The CO2/bi/carbonate loss while the surface layer floates around the equator is influenced by biomass production which is especially high at the upwelling places, thus not a unique loss to the atmosphere.

Ferdnand.
I did a comparison of the four values at 10S in NOAA’s report Fig.5 with the monthly values (from 1981 to 2012) that I calculated for 10S from 90W to 135W with these results. Expressed as kg/m^2/year, NOAA average 0.0407 with standard deviation of 0.0157, my analysis 0.020 average with a standard deviation of 0.0083. If I had assumed two meters rather than one, the values would be very nearly the same. In the future I will use two meters and calculate the higher values at different locations. Variations in windspeed will average out in monthly measurements.

Gunga Din says: June 29, 2013 at 10:57 am
“Don’t you mean calcium bicarbonate?”
I am considering your question. In fresh water the Co2 is dissolved and becomes a bicarbonate due to the low Ph of rain water. This reacts with the calcium hydroxide to form calcium bicarbonate. When the calcium bicarbonate reaches the ocean, does the high Ph cause it to disassociate into ions and reform as calcium hydroxide and two carbonates? Something happens that forms calcium hydroxide. I will go back and see if I can find this in my chemistry books.

fhhaynie says June 29, 2013 at 11:38 am
Thanks for responding to my question. What I am trying to establish is whether or not there is a non-biological production of calcium carbonate. When I read the literature I find that there are differences of opinion on whether it exists. It is particular interesting to read accounts of calcium carbonate whitings in the Persian Gulf and the Bahamas. Also magnesium appears to inhibit the reaction. One primitive laboratory test for carbon dioxide is to bubble the gas through a solution of calcium hydroxide and watch the solution turn milky as calcium carbonate is formed. The ocean is saturated with calcium hydroxide and I am interested in what happens when the ocean heats and carbon dioxide comes out of solution. If there are unique things that inhibit the reaction, I would like to know what they are.

John,
Most of the carbon in the oceans is inorganic and there is a lot more of it than organic. DICs (dissolved inorganic carbons) will precipitate along with organics when they reach saturation on warming. The ratio of C13 to C12 is a measure of what comes from organics.

Ferdinand Engelbeen says June 29, 2013 at 10:55 am
I realize that the dissolving of major amounts of limestone requires a very long time, perhaps even thousands of years. However, the bottom of the shallow oceans are covered with so much calcium carbonate that it looks like snow. Hydrated (dissolved) calcium carbonate is also found on the ocean floor and shorelines in the form of mineral rocks as well as in solution. This has been going on for a long time, we should have run out calcium if we didn’t have a robust supply coming into the ocean.

I am considering your question. In fresh water the Co2 is dissolved and becomes a bicarbonate due to the low Ph of rain water. This reacts with the calcium hydroxide to form calcium bicarbonate. When the calcium bicarbonate reaches the ocean, does the high Ph cause it to disassociate into ions and reform as calcium hydroxide and two carbonates?

It is the other way out: CO2 + water in rainwater reacts as carbonic acid (H2CO3), with CaCO3 and MgCO3 (carbonates) to form bicarbonates as Ca(HCO3)2 and Mg(HCO3)2. These are soluble in fresh water and in the oceans in the form of Ca++ and Mg++ ions at one side and HCO3- ions at the other side. The solubility is in a wide range of pH: from acid to at least pH 8.5. Above that carbonate ions are increasing leading to the precipitation of again CaCO3 and/or MgCO3. To form hydroxides of Ca and Mg, you are in a higher pH range, anyway leading to precipitation of the Ca en Mg carbonates. Of course, there are always hydroxyl ions present, but they play no role in the above reactions.

The solubility of carbonate rock is the result of the low pH of CO2 containing rain (slightly acidic). The (deep) oceans are slightly basic, thus not so readily dissolving carbonates, but under pressure, some of the chalk deposits still may dissolve. On the other side, the biological pump (coccoliths) drops some of these cabonates back down to the ocean floor. That is more or less in equilibrium, where slightly more is deposited than dissolved, especially in more shallow seas. In ancient times, that were e.g. the deposits of Southern England (and French Calais and Normandy), still visible as the white cliffs of Dover and beyond.

Thank you both for your answers. I am pleased to find some experts in this field. If you will bear with me I would like to ask some questions and show you why I am interested in this particular chemistry.
There is an energy exchange when CaCO3 is formed. When Ca(HCO3)2 reacts, it is exothermic with CO2 being released. When CaCO3 is formed from Ca ions and Co2 it is endothermic. The endothermic reaction that I reference removes about 1400 Kjoules per mole of CaCo3. This energy is removed from the ocean and stored as chemical energy. I have read a considerable number of papers on the ocean and while I see a lot of chemical reactions, I never see the number of joules of energy that accompany the reaction. Is there a reason for this. I see the ocean as a big chemical factory with a lot of reaction that store energy and remove it from the environment. In addition to the reaction that I mentioned, there are the hydration reactions.

Although only roughly known, the net deposit of carbonates on the seafloor is about 2 GtC or about 17 Gt CaCO3. That is peanuts compared to the total mass of the ocean surface, where most of the thermal and chemical reactions take place, including photosynthesis, which absorbs parts of the solar spectrum. Only a small part of that energy is used by algue to build their shells of which a small part falls out of the surface layer of the oceans to the bottom.

Thus in my opinion, the energy transfer of this reaction is not even measurable in the large energy transfers from the sun to the oceans in general and specific into algue energy buildup.

John,
I think the biggest mistake that climate modelers make is to assume that the earth is naturally in some kind of “dynamic equilibrium” with respect to energy, being upset by the anthropogenic contribution of CO2 to the atmosphere. The fact that the earth rotates and tilts with respect to the sun prevents it from ever being in equilibrium or even in a steady state. It is always changing chasing a moving target like thermodynamic equilibrium. The best we can do is to observe those changes and try to figure out what to expect in the future. Personally, I think that the processes of evaporation/condensation and freezing/thawing are the thermostats that make the earth favorable for life.

Ferdinand Engelbeen says: June 30, 2013 at 9:27 am
“Although only roughly known, the net deposit of carbonates on the seafloor is about 2 GtC”
Thus in my opinion, the energy transfer of this reaction is not even measurable in the large energy transfers from the sun to the oceans in general and specific into algue energy buildup.
I assume that your answer as to why the energy from chemical reactions in the ocean are not listed is that it is not significant. I believe that the 2 GtC number that you quote is from nets that sample shells etc. as they descind into the ocean. It is not clear to me that nets would properly sample non-biological CaCO3 precipitate. I will convert the 17Gt CaCO3 to joules and see if there is enough energy to be significant.
When I look at the graphs of the temperatures of the Argo floats, the ascending and descending temperatures, the repeatability of the temperatures from year to year are to precise to be caused by winds or clouds. The ocean’s maximum temperature of 30.5C to 31C is also the maximum of inland lakes both large and small. I believe that such precision can only be caused by a chemical reaction and my best candidate is the calcium carbonate reaction.

fhhaynie says: June 30, 2013 at 6:17 am John,
“Most of the carbon in the oceans is inorganic and there is a lot more of it than organic. DICs (dissolved inorganic carbons) will precipitate along with organics when they reach saturation on warming. The ratio of C13 to C12 is a measure of what comes from organics.”
Do you have the ratio of C13 to C12? I can get an understanding of the amount of inorganic carbon by comparing it to number on the Oregon State website.

John,
As far as I know, the global distribution in sea water as a time function has not been determined. We do have a good bit of data for air in the form of the C13/C12 index. You can estimate the ratio in air by assuming some average index value for that from organic sources (I have used -27.5) and dividing into the measured and calculated index. This assumes that the other fraction has an index of zero (the inorganic PDB standard). The atmospheric index values are a mirror image of the atmospheric concentrations of CO2 so one should expect that the relationships between sea and are to be similar. This, however, is complicated by an annual cycle of fractionation processes (within the biosphere and possibly clouds). The Scripps column 10 factors out these annual cycles.
Click on my name for more detail.

After reviewing the C13/C12 data on the web, and thinking about what it means, I don’t see how this ratio can be used to calculate the non-biological calcium carbonate production. There is really no connection between the two.

It gives you an idea about the the fraction of CO2 dissolved in sea water that has gone through a fractionation process and is depleted in the heavier molecule. The other fraction is expected to be from inorganic sources. Both fractions can precipitate as CaCO3. It is possible that the precipitation process preferentially depletes the lighter molecule so that what settles on the bottom is more like the PDB standard.

I agree. The other complication is that the ratio measured in the precipitated CaCO3 is probably more depleted in the lighter CO2 molecule than the desolved CO2 from which it formed. I’m more interested in what goes into the air than what is precipitated.

After thinking about it, takes a while for a 73 year old to remember sometimes, I recall a paper that two young researchers at one of the west coast research facilities published that used C13/C12 ratios to recalculate ocean productivity. I don’t remember the details, but it should contain C13/C12 data for some ocean product. I will look for that paper.